Mastercraft Courser STR All-Season Radial Tire - 235/75R15 105S Modern Highway Design: The modern highway tread pattern is for popular crossover, SUV and light pickup vehicles. Semi-Solid Center Rib: Provides a smooth ride and comfortable on-center feel. Circumferential Grooves: See-through grooves help disperse water and slush from the tread to provide dependable all-season traction. Variable Pitch Tread: Computer-designed to provide a quiet-running tire at highway speeds. M+S Rated All-Season Grip.